The construction and implementation of a multichannel loudspeaker array for accurate spatial reproduction of sound fields

Abstract

The spatial distribution of sound has a strong impact upon a listener’s overall impression of a room and must be reproduced accurately for auralization. In concert hall acoustics, directionally independent metrics such as reverberation time and clarity index simply do not predict this impression. Late lateral energy level, lateral energy fraction, and the interaural correlation coefficient are measures of spatial impression, but more work is needed before we fully understand how the directional distribution of sound should influence architectural design decisions. A three-dimensional array of 28 loudspeakers and two subwoofers has been constructed in a hemi-anechoic chamber at PSU, allowing for accurate reproduction of sound fields. For the array, closed-box loudspeakers were built and digitally equalized to ensure a flat frequency response. With this facility, subjective studies investigating spatial sound in concert halls can be conducted using measured sound fields and perceptually motivated auralizations, not tied to a physical room. Such a facility is instrumental in understanding and communicating subtle differences in sound fields to listeners, whether they be musicians, architects, or clients. The flexibility and versatility of this system will facilitate room acoustics research at Penn State for years to come. [Work supported by NSF Award 1302741.]